Luis Chung JoonYoung Park A Wristwatch for the Visually Impaired ECE 445 Senior Design Spring 2016 Team 62 Mock Presentation 28 April 2016

CONTENTS 1. Introduction 2. Objective 3. Block Diagram 4. Schematic 5. Power Supply 6. Mathematics 7. Waveform 8. Requirement and Verification 9. Conclusion

Introduction There have not been many developments for the physically impaired individuals l With the press of a button, the user will be able to read the braille on the face and tell the precise time. l Braille would improve current watches for the blind with a braille interface and a vibrating buzzer The watches, currently in the market, only provide a general sense of time

Objective Goals and Benefits The purpose of Braille is to develop a precise time telling watch for the visually impaired. l Allow for more convenient life for the visually impaired l Provide accurate telling of time via GPS l Allow for single-handed time telling via buzzer Functions and Features l On-board braille for precise time l Vibrating buzzer to tell time single-handed l Automatic time zone synchronization via GPS

Block Diagram Block Diagram for Entire System

Schematic Schematic for Entire System [3] Switches Microcontroller Power Supply Buzzer Braille GPS

Power Supply Voltage Regulator LM7805AC [4] l Convert 9V to 5V l Supply 5V to the system (i.e. Switches, Microcontroller, Braille Driver, Buzzer Driver) Voltage Regulator Schematic [3] LM7805AC [4]

Power Supply with High Side Gate Driver (LTC ) DC Buck Converter DC-DC Buck Converter Schematic with LT-Spice [5]

Mathematics l For the inductance, DC Buck Converter 40uH Inductor [2]

Mathematics l For the capacitance, DC Buck Converter 22uF Capacitor [1]

LT-Spice Waveforms for the Buck Converter’s Output [5] DC Buck Converter Waveform

Req.&Veri. l Power supply must step down 9V - 18V to 5V±5% Requirement l Power supply must achieve an efficiency of 70% or greater l The power supply must provide continuous current of 1A±10% to each solenoid Verification l With the digital multi-meter, output voltage and current can be measured l Bench supply generates 9V±10% to the power supply’s input

Conclusion l Will embed real time clock to keep track of time when GPS goes out of sync l Minimize solenoids to reduce power consumption Future Work l Utilize DC-DC buck converter to PCB layout

Work Cite [5] LT Spice. [Software]. Milpitas, CA: Linear Technology, [1] "22uF 100V Radial Electrolytic Capacitor Nichicon UPJ2A220MPD1TD." West Florida Components. Web. 25 Apr [4] Lm78XX/LM78XXA 3-Terminal 1 A Positive Voltage Regulator. N.p.: 2006 Fairchild Semiconductor Corporation, Sept PDF. [2] "B82111 Series." Digi-key Electronics. Web. 25 Apr [3] Eagle CAD. [Software]. Pembroke Pines, FL: CadSoft Computer, 2011.

Thank you Do you have any questions? Gratitude